In the Dominican Republic, depression is rarely treated until a person is severely ill and unable to perform activities of daily living. This is due to the unavailability of antidepressants, the cost of and logistical barriers to obtaining psychotherapy, stigma, and low mental health literacy which preclude recognition of depression. Health care delivered through mobile devices (known as mHealth) could surmount many of these barriers due to its ease of access and privacy. Guided mHealth to deliver mental health interventions (MHapps) have been shown to be effective in High Income Countries, (HICs). However, in Low and Middle-Income Countries (LMICs), where access to health care is limited, there have been few interventional research studies conducted using MHapps. The purpose of this project is to develop processes to ensure feasible dissemination of the app within an integrated primary care - behavioral health care setting and to evaluate its implementation. The app, El Buen Consejo Mvil (EBCM) has the functionality to connect individuals to one another via a CHW-guided chat room (ECBM-G) or to receive the same contents as an individualized program without the group functionality. The app allows users to communicate with others or their CHW guide using voice and text. This research builds upon several recently funded studies in the DR which: explored stigma and mental health service delivery; modified the contents of an evidenced-based CBT depression prevention course for Dominicans; and further modified this course for use in an MHapp. In the proposed study, we will refine the app and increase capacity for integrated primary care- behavioral health care for depression. We will conduct a randomized controlled trial in a primary care clinic in Santo Domingo among 120 patients who screen positive for mild to moderate depression on the Patient Health Questionnaire (PHQ-9). The MHapp will be downloaded to the participant?s own Android phone. We will evaluate process outcomes for CHWs and primary care staff, including 1) feasibility, 2) fidelity, 3) acceptability, and 4) perceived confidence in identifying and managing patients? symptoms of depression. The primary outcomes for app users will be acceptability of the app and perceptions of social interactivity for those randomized to the group condition. We will assess the acceptability of EBCM, and, for users randomized to the group condition, perceptions of social interactivity using the Computer-Mediated Communication Questionnaire rating scale and open-ended questions. The Online Social Support Scale will be administered to measure perceptions of peer social support in the domains of Emotional Support, Social Companionship, Informational and Instrumental Support. Level of adherence and effectiveness, the secondary outcomes, will be assessed by frequency of interaction with the MHapp, completion of treatment for either treatment modality, and change in depressive symptoms. We hypothesize that the use of MHapps for guided self-help can be enhanced through group interaction. EBCM potentially will expand mental health service delivery in LMICs, for primary care patients who rarely seek care for depression.